THE BLOOD VITAMIN B12CONCENTRATION OF OLDER PATIENTS ADMITTED TO A NEUROLOGICAL DEPARTMENT

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Abstract
The blood vitamin B12 concentration was measured in a consecutive series of 127 patients above the age of 65 and younger patients. Twenty-one patients (16. 5%) showed concentrations below 200 pg/ml. 15 patients (11. 8%) showed values below 165 pg/ml. With one exception all of the values were above 100 pg/ml. Nine of these patients (7.1%) showed signs of an impaired absorption of the vitamin (4 patients) or a subnormal effect upon the bone marrow of vitamin B12 (6 patients). Values above 600 pg/ml may be pathologically high in older patients, and that further investigations are warranted in such patients. At least 50% of the 18 patients with vitamin B12 concentrations above this limit presented abnormal liver function tests. A correlation between the vitamin B12 level of the blood and the intake of foods, rich in vitamin B12, was only apparent in patients with a secretion of free hydrochloric acid. Achlorhydria was more often encountered in the patients belonging to the older group[long dash]and especially among the patients with a vitamin concentration below 200 pg/ml[long dash]than in the group of younger patients. A modest oral intake of vitamin B12 and intrinsic factor evoked in the course of 2 weeks in all of 9 patients examined an unequivocal rise of the blood concentration of vitamin B12. Correlations between the low plasma concentrations of vitamin B12 and the presence of paraesthesiae or a reduction of vibration sense could notbe detected.